BKDR_SIMDA.OFP

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

As of this writing, the said sites are inaccessible.

It deletes the initially executed copy of itself.

Arrival Details

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This backdoor drops the following files:

• %Application Data%\{random name}.reg
• %Application Data%\mcp.ico
• %Desktop%\Computer.lnk
• %User Temp%\{random name}.sys
• %User Temp%\{random number}.tmp
• %User Temp%\{random name}.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It drops the following copies of itself into the affected system:

• %Application Data%\ScanDisc.exe
• %Application Data%\{random name}.exe
• %User Temp%\{random number}.tmp

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
{random name} = "%Application Data%\{random name}.exe"

Other System Modifications

This backdoor adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
ConsentPromptBehaviorAdmin = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
ConsentPromptBehaviorUser = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = "0"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows
update = "shortcut"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

• Download and execute arbitrary files
• Remote shell

It connects to the following URL(s) to send and receive commands from a remote malicious user:

• http://{BLOCKED}.{BLOCKED}.243.64/chrome/report.html
• http://{BLOCKED}.{BLOCKED}.12.201
• http://{BLOCKED}.{BLOCKED}.83.117
• http://{BLOCKED}.{BLOCKED}.38.173
• update.{pseudorandom}.com
• report.{pseudorandom}.com
• http://{BLOCKED}.{BLOCKED}.216.6

It posts the following information to its command and control (C&C) server:

• OS information
• Drive information

However, as of this writing, the said sites are inaccessible.

Download Routine

This backdoor accesses the following websites to download files:

• http://{BLOCKED}1.{BLOCKED}string.com/?abbr=RTK&setupType=update&uid={random number}&ttl={random string}&controller=microinstaller&pid=3
• http://{BLOCKED}1.{BLOCKED}string.com/update_c1eec.exe
• http://{BLOCKED}1.{BLOCKED}main.com/?abbr=RTK&action=download&setupType=umx&setupFileName=process_64.exe
• http://{BLOCKED}1.{BLOCKED}string.com/?controller=hash

It saves the files it downloads using the following names:

• %User Temp%\{random number}.exe
• %System Root%\text.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

As of this writing, the said sites are inaccessible.

HOSTS File Modification

This backdoor modifies the system's HOSTS files to redirect users once the following Web site(s) are accessed:

• www.google-analytics.com
• ad-emea.doubleclick.net
• www.statcounter.com

Other Details

This backdoor checks for the presence of the following process(es):

• Aircrack-ng Gui.exe
• apis32.exe
• CamRecorder.exe
• CamtasiaStudio.exe
• cv.exe
• DrvLoader.exe
• dumpcap.exe
• ERDNT.exe
• ERUNT.exe
• EtherD.exe
• irise.exe
• IrisSvc.exe
• observer.exe
• ollydbg.exe
• PEBrowseDbg.exe
• Regshot.exe
• SandboxieDcomLaunch.exe
• SandboxieRpcSs.exe
• SbieCtrl.exe
• SbieSvc.exe
• Sniffer.exe
• SUPERAntiSpyware.exe
• SymRecv.exe
• Syser.exe
• tcpdump.exe
• VBoxService.exe
• VBoxTray.exe
• windbg.exe
• WinDump.exe
• wireshark.exe
• wspass.exe
• ZxSniffer.exe

It deletes the initially executed copy of itself

NOTES:

It checks for the following registry keys:

AppEvents\Schemes\Apps\Bopup Observer
SOFTWARE\APIS32
Software\B Labs\Bopup Observer
Software\Classes\*\shell\sandbox
Software\Classes\Folder\shell\sandbox
SOFTWARE\Classes\PEBrowseDotNETProfiler.DotNETProfiler
SOFTWARE\Classes\SUPERAntiSpywareContextMenuExt.SASCon.1
Software\CommView
SOFTWARE\Cygwin
Software\eEye Digital Security
SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\wireshark.exe
Software\Microsoft\Windows\CurrentVersion\Explorer\MenuOrder\Start Menu2\Programs\APIS32
Software\Microsoft\Windows\CurrentVersion\Explorer\MenuOrder\Start Menu2\Programs\Debugging Tools for Windows (x86)
SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\APIS32
SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ERUNT_is1
SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Oracle VM VirtualBox Guest Additions
SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Sandboxie
SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Win Sniffer_is1
SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Wireshark
SOFTWARE\SUPERAntiSpyware.com
Software\Syser Soft
Software\Win Sniffer
SOFTWARE\ZxSniffer
SYSTEM\CurrentControlSet\Services\IRIS5
SYSTEM\CurrentControlSet\Services\SbieDrv
SYSTEM\CurrentControlSet\Services\SDbgMsg
SYSTEM\CurrentControlSet\Services\VBoxGuest

If the said processes or registry keys are found, it does not continue to perform its intended routine.

It also redirects to the following URL when the user attemps to search using the specific domains:

• http://{BLOCKED}la.com/?&uid=%d&q={searchTerms}

It also attempts to open the file %System Root%\cgvi5r6i\vgdgfd.72g.